B. Guezzen and  M. A. Didi and  B. Medjahed,  Sorption of Congo Red from Aqueous Solution by Surfactant-Modified Bentonite: Kinetic and Factorial Design Study .   journal   = {International Journal of Chemical and Molecular Engineering}, [online]. World Academy of Science, Engineering and Technology.
    February 2018, vol. 135(3). 169 - 176
    [viewed 12 December 2019]. Available from: https://publications.waset.org/pdf/10008754.